Biochar Amendments in Soil: A Sustainable Approach for Mitigating Heavy Metal Stress in Plants

Heavy metal (HM) accumulation in soil poses a major hazard to both ecological health and plant growth progressions. Cadmium (Cd), lead (Pb), copper (Cu), chromium (Cr), arsenic (As), zinc (Zn), and nickel (Ni) are examples of HMs that negatively impact the growth and development of plants, resulting in lower agricultural output and food safety concerns. Biochar (BC), a substance rich in carbon that is formed by pyrolyzing natural biomass, has demonstrated remarkable promise in reducing HM stress in polluted soils. Research has shown that BC effectively lowers plant uptake of metals, and enhances soil qualities, and encourages microbial activity. Besides, BC improves the fertility of soil, retention of water, and nutrient absorption, while it interacts with soil microbes to help mitigate the negative effects. However, a number of variables affect how effective BC is as a soil supplement, including the kind of BC used, the soil’s characteristics, and the metal’s qualities. This review delves into the mechanisms of BC’s interactions with HMs, its potential to mitigate stress caused by different metals, and the factors that influence its efficiency. Furthermore, it draws attention to the drawbacks and difficulties associated with using BC in heavy-metal-contaminated soils, offering suggestions for future studies focused on maximizing its utilization for long-term soil rehabilitation and sustainable agriculture.